The former president of the Bangladesh Cricket Board, Saber Hossain Chowdhury, is believed to have been arrested in a campaign by the government that has been strongly criticised by Amnesty International.

Chowdhury and others are reportedly held under the government's "Operation Clean Heart" initiative, which is billed as a crackdown on crime by the army and police. But Amnesty is urging an immediate investigation into allegations of deaths in custody and torture.

"The government must bring to justice any army or police personnel involved in the torture of detainees, and clarify the legal status of the army's involvement in arrests of civilians," said Amnesty.

Chowdhury is political secretary to the leader of the opposition, Sheikh Hasina, and is thought to have been arrested earlier this week. Amnesty claims over 2000 people have been arrested and at least five people have died in custody in the operation.

Amnesty believes that Chowdhury, along with Sheikh Fazlul Karim Selim, a member of parliament and former health minister, are possible prisoners of conscience. No details have been made public about the possible charges against them, and Amnesty fears they may be detained solely for their peaceful opposition to the government.

"It is every government's duty to ensure law and order for the benefit of all citizens, but this cannot be imposed at the expense of the basic rights of the people", Amnesty International said.

As president of the Cricket Board, Chowdhury was a key figure behind Bangladesh's elevation to Test status two years ago.